Design a Dictionary for Heterogeneous Key and Value Types

Design a key-value dictionary whose keys and values may have different types and lengths. Explain hashing, equality, collision handling, and storage ownership. ### Constraints & Assumptions The reported prompt asks about arbitrary types and variable-length storage. This is an interface and representation discussion, not a demand that every runtime object automatically be a safe key. State which types are supported and how callers supply hashing or equality for custom types. ### Clarifying Questions Are types known at compile time or erased at runtime? Should integer 1 and string `1` be distinct keys? Can keys mutate after insertion? Is the dictionary in memory or serialized persistently? ### What a Strong Answer Covers A consistent equality/hash contract, typed representation, collision resolution, lifetime management, and realistic complexity including variable-length keys. ### Follow-up Questions How would resizing work? How do you handle a poor or adversarial hash function? Why is hashing raw object memory unsafe for many types? What changes for persistence across process versions?